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European Society of Cardiology, BJC Arrhythmia Watch

Clinical Articles, Lead Article

Flec-SL trial shows efficacy of antiarrhythmic treatment

Short-term antiarrhythmic drug treatment after cardioversion is nearly as effective in preventing recurrences of atrial fibrillation as long-term treatment, according to results from the Flec-SL (flecainide short – long) trial, conducted by the German Competence Network on Atrial Fibrillation (AFNET). The scientific paper was published recently in The Lancet.1

AFNET, the German Competence Network on Atrial Fibrillation, performed a randomised clinical trial to investigate whether a short-term antiarrhythmic drug treatment for the duration of four weeks after cardioversion could prevent recurrences of AF as effectively as the usual long-term treatment.

This was assessed using the approved drug flecainide. The Flec-SL trial was conducted by AFNET under the direction of principal investigators Professor Paulus Kirchhof, and Professor Guenter Breithardt, both prominent members of EHRA, the European Heart Rhythm Association of the European Society of Cardiology (ESC).

Between May 2007 and March 2010, more than 600 patients were enrolled in the study at 44 centres in Germany. Patients were randomised to different groups where they were treated with flecainide for either four weeks or six months. Additionally, there was a control group without antiarrhythmic drug treatment. In all study patients, recurrences of AF were assessed by daily trans-telephonic ECGs within the observation period of six months.

Professor Paulus Kirchhof

Professor Paulus Kirchhof

Analysis of the study data reveals: antiarrhythmic long-term treatment is superior to short-term treatment, but also the four-week short-term treatment was able to prevent recurrences of AF: AF relapses occurred in 120 of 261 patients receiving short-term treatment and only in 103 of 263 patients receiving long-term treatment. At the end of the study, short-term therapy reached about 80% of the effect of long-term therapy.

Principal investigator Professor Kirchhof (Centre for Cardiovascular Sciences, University of Birmingham, UK 
Department for Cardiology and Angiology, University Hospital Muenster) is sure that these findings have implications for clinical routine: “Although antiarrhythmic short-term treatment is inferior to long-term treatment, it will be useful in selected patients. Short-term treatment should be considered for AF patients who are at increased risk for complications or adverse effects. We hope that the new results find their way into guidelines for the management of AF”.

Speaking to BJC Arrhythmia Watch, Professor Kirchhof said: “The Flec-SL trial used flecainide to test the concept of short-term antiarrhythmic drug therapy. We found that short-term therapy is slightly less effective than long-term therapy, but that short-term therapy retains approximately 80% of the antiarrhythmic effect at 6 months after cardioversion, with very similar effects on quality of life compared to long-term therapy. Hence, short-term therapy may be considered in patients in whom drug-induced side effects are a concern, or in those in whom recurrence risk appears low”.

He continued: “The therapeutic concept of short-term antiarrhythmic drug therapy has only been tested in Flec-SL using flecainide. While we do not have controlled trial data, short-term therapy may be useful for other antiarrhythmic drugs that prolong the cardiac action potential as well. It would be acceptable to most to transfer the results to therapy with propafenone, based on the very similar ion channel blocking profile of propafenone and sotalol. Sotalol and dronedarone could also be used as agents for short-term therapy when safety is a concern. Amiodarone, in contrast, would not be suitable for short-term therapy due to its long biological half life”.


1. Kirchhof P et al. Short-term versus long-term antiarrhythmic drug treatment after cardioversion of atrial fibrillation (Flec-SL): a prospective, randomised, open-label, blinded endpoint assessment trial. Lancet 2012.

Published on: July 24, 2012

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